Suggested starting exposure times in J-band mode for an H-magnitude=5 is 45 seconds when observing with a coronagraph.
The zero-point of each channel in J-band mode is given below, the max zero-point is J = 17.8 mag.
The curve below shows the 2-read saturation limit with no coronagraph. The maximum allowable magnitude to avoid saturation is J = 7.2 mag
NOTE: Throughput of SCExAO rebuild and AO performance on any particular night will affect these numbers. Strehl ratios of 60-80% were estimated when this data was taken